Debt and Credit Facilities - Debt and Related Weighted Average Contractual Interest Rates (Details) - USD ($) $ in Millions	Jun. 30, 2023	Mar. 31, 2023
Debt Instrument [Line Items]
Debt, Face value	$ 112,865	$ 112,170
Debt, Carrying value	$ 112,376	$ 111,685
Weighted average contractual interest rates	3.79%	3.56%
Unsecured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 81,354	$ 79,393
Debt, Carrying value	$ 80,912	$ 78,949
Weighted average contractual interest rates	3.69%	3.48%
Secured notes and loans payable [Member]
Debt Instrument [Line Items]
Debt, Face value	$ 31,511	$ 32,777
Debt, Carrying value	$ 31,464	$ 32,736
Weighted average contractual interest rates	4.02%	3.76%